package com.bl.utils;

import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * Created by mrt on 2018/3/27.
 */
public class GenerateOrderNum {
     /**
      * 锁对象，可以为任意对象
      */
     private static final Object lockObj = "lockerOrder";
     /**
      * 订单号生成计数器
      */
     private static long orderNumCount = 0L;
     /**
      * 每毫秒生成订单号数量最大值
      */
     private final int maxPerMSECSize = 1000;

     /**
      *
      */

     public static void main(String[] args) {
          // 测试多线程调用订单号生成工具
        /*try {
            for (int i = 0; i < 200; i++) {
                Thread t1 = new Thread(new Runnable() {
                    public void run() {
                        GenerateOrderNum generateOrderNum = new GenerateOrderNum();
                        generateOrderNum.generate("a");
                    }
                }, "at" + i);
                t1.start();

                Thread t2 = new Thread(new Runnable() {
                    public void run() {
                        GenerateOrderNum generateOrderNum = new GenerateOrderNum();
                        generateOrderNum.generate("b");
                    }
                }, "bt" + i);
                t2.start();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }*/
          System.out.println(System.currentTimeMillis());
     }

     /**
      * 生成非重复订单号，理论上限1毫秒1000个，可扩展
      *
      * @param tname 测试用
      */
     public synchronized String generate(String tname) {
          try {
               // 最终生成的订单号
               String finOrderNum = "";
               synchronized (lockObj) {
                    // 取系统当前时间作为订单号变量前半部分，精确到毫秒
                    long nowLong = Long.parseLong(new SimpleDateFormat("yyyyMMddHHmmssSSS").format(new Date()));
                    // 计数器到最大值归零，可扩展更大，目前1毫秒处理峰值1000个，1秒100万
                    if (orderNumCount >= maxPerMSECSize) {
                         orderNumCount = 0L;
                    }
                    //组装订单号
                    String countStr = maxPerMSECSize + orderNumCount + "";
                    finOrderNum = nowLong + countStr.substring(1);
                    orderNumCount++;
                    //System.out.println(finOrderNum + "--" + Thread.currentThread().getName() + "::" + tname );
                    // Thread.sleep(1000);
                    return finOrderNum;
               }
          } catch (Exception e) {
               e.printStackTrace();
          }
          return "";
     }
}
